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Prep4USMLE Forum » USMLE Step 1 Forum » Biochemistry Forum

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3 Posts

yakuzar
Forum Newbie

Topics: 1
Posts: 4

11/21/05 - 01:14 PM

55 year old male with hypertension and a PMH of MI is given propranolol. This medication will lower BP by
A. blocking catecholamine release
B. blocking the conversion of Ang I to Ang II
C. decreasing cardiac output
D. decreasing intravascular volume
E. increasing renin release from the kidney

jonathon
Forum Senior

Topics: 25
Posts: 62

11/21/05 - 02:35 PM

I think its c. by decreasing cardiac output. propanalol is a beta-blocker and exerts its effects by blocking the beta-1 receptors in the cardiac muscle. as a result there is a decrease in the force of contraction and hence the cardiac output decreases as well

robin082006
Forum Hero
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Topics: 471
Posts: 5,125

11/21/05 - 11:58 PM

Beta-blocker decrease cardial muscle contractivity (stroke volume) and heart rate. Because CO= stroke volume X heart rate so C is correct.

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